B. Check voltage levels recorded on both placards on face of compensator. On airplanes with aluminum foil adjustment markers installed on brackets adjacent to magnetic compensators, check voltage levels recorded on these aluminum foil adjustment markers.
C. Carefully record these values on respective placards of replacement unit.
NOTE: Loss of these voltage values will require that a complete new
____
airplane compass swing be performed.
D. Loosen quick-release fasteners and remove unit.
E. Disconnect electrical connector at rear of unit.
5. Install Magnetic Compensator
____________________________
A. Check or record voltage information on placards of compensator to be installed. Use data from N-S and E-W placards on previously installed unit. On airplanes with aluminum foil adjustment markers installed on brackets adjacent to magnetic compensators, use N-S and E-W data recorded on these aluminum foil adjustment markers.
NOTE: Failure to correctly transfer these voltages would make a complete
____ airplane compass swing procedure necessary before MHRS is operational.
B. Attach electrical connector on rear panel of unit and install with quick-release fasteners.
C. Close MHRS 1 or MHRS 2 circuit breaker (panel P7).
D. Using a calibrated voltmeter, measure voltage between N-S (+) and common (-) test points on front of compensator.
NOTE: Do not select lower than 2.5 V DC range on voltmeter except when
____ using DVM/VTVM, as meter loading may cause reading errors.
E. Adjust N-S control until voltage level equals N-S placard value (within
0.1 volt dc) and secure N-S control.
EFFECTIVITY
ALL 04 Page 401 Apr 25/7934-21-02
F. Using calibrated voltmeter, measure voltage between E-W (+) and common (-) test points on front of compensator.
NOTE: Do not select lower than 2.5V DC range on voltmeter except when
____ using DVM/VTVM, as meter loading may cause reading errors.
G. Adjust E-W control until voltage level equals E-W placard value (within
0.1 volt dc) and secure E-W control.
H. Recheck both N-S and E-W calibration voltages and readjust as necessary until voltages remain stable.
EFFECTIVITY
ALL 05 Page 402 Jan 25/7934-21-02
MAGNETIC COMPENSATOR - ADJUSTMENT/TEST
______________________________________
1. Magnetic Compensator Test
_________________________
A. Referenced Procedures
(1)
21-58-00, Equipment Cooling - Adjustment/Test (Operational Test)
(2)
24-22-00, Manual Control - Maintenance Practices (Apply Power)
(3)
34-21-00, Magnetic Heading Reference System - Adjustment/Test (Operational Test)
(4)
34-41-00, Inertial Navigation System - Adjustment/Test (Operational Test)
B. Prepare for Test
(1)
Apply airplane power (Ref 24-22-00).
(2)
Supply equipment cooling to main equipment center shelves (Ref 21-58-00).
CAUTION: IF OPERATED WITHOUT PROPER COOLING, DAMAGE TO ELECTRONIC
_______
EQUIPMENT COULD RESULT.
(3)
Turn on inertial navigation systems No. 1 and No. 2. Ensure that they are operating in NAV mode with present position inserted. Main power, platform heading and HSI circuit breakers must be closed (Ref 34-41-00).
(4)
Set both VOR/ILS-INS switches to VOR/ILS.
(5)
On ALL EXCEPT AT ALL,
set captain's COMPASS switch to CAPT 1-F/O 2.
On AT ALL,
set captain's COMPASS switch to NORM.
(6)
Set captain's ATT/COMP STAB switch to CAPT 1 - F/O 2.
(7)
On ALL EXCEPT AT ALL, set captain's ATT/COMP STAB switch to CAPT-1-F/O 2. On AT ALL, set captain's ATTITUDE switch to NORM.
C. Test Magnetic Compensator
(1)
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